Access flooring systems were originally employed in computer systems and have, over the years, found diversified applications in differing fields such as office environments laboratories, communication facilities, hospitals, clean rooms and other instances wherein the advantages of creating and utilizing a space between a load supporting flooring and a structural subflooring became evident. Access flooring systems have been utilized to conceal electrical wiring, telephone cables, computer communications cable networks, air conditioning duct work, plumbing lines, fire and smoke detection systems and other systems, yet permitted access for maintenance, additions and alterations.
Basic access flooring systems included rectangular floor panels of metal which were reinforced or, metal covered composition wood cores. The floor panels were supported at an elevation above the subfloor by spaced pedestals which were capable of height adjustment. In gridless systems, the pedestal heads were positioned beneath the corners of four abutting panels so that each panel was supported by a pedestal at one of its corners.
In instances wherein increased stability and load capacity were required, the pedestals included heads to which horizontally oriented perpendicular stringers were attached. The grid was formed so that each stringer was registered with and positioned beneath an edge of a rectangular panel. The grid system thus provided additional support for each panel along its entire periphery. Some access flooring systems such as illustrated in U.S. Pat. No. 3,396,501 additionally included provisions for clamping devices to secure stringers to the pedestal heads to prevent displacement.